Compressor-unloading mechanism



M. RIESNER COMPRESSOR UNLOADING MECHANISM Original Filed Jan. 10 192] ZVENTOR BY HIS ATTORNEYS Oct. 7 I 1924.

Patented 0.... 7, 1924.

- UNI-TED STATES PATENT oF lcs.

MICHAEL RIF-SNER, OF CINCINNATI, OHIO, ASSIGNOR T WORTHINGTON PUMP AND MACHINERY CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF VIRGINIA.

COMPRESSOR-UNLOADIING MiscnAnIsM.

' Amman filed January 16, 1921, Serial No. 436,036. Renewed August 8,1922. Serial No. 580,565.

To all whom it may camera:

Be it known that I, MICHAEL RmsNER,

I a citizen of the United States, residing at Cmclnnati, county of Hamilton, and State of Ohio, have invented certain new and useful Improvements in Compressor-Unloadlng Mechanism, fully described and represented in the following specification and the 16 accompanying drawings, forming a part of the same. Thepresentinvention relates to improvements in compressor unloading mechanism. It is the especial object of the invention to provide an improved speed-controlled unloading mechanism for air compressors, by

V which pressure air is by-passed to the at have difliculty mosphere through a connection controlled by a valve adapted to cooperate with a governor-controlled pilot valve on a compressor discharge connection, which will permit the compressor driving motor to -attain approximately full speed before compressing action begins, and also relieve the pressure when the power is shut off, thereby.

avoiding jerking strain on the compressor belt or other driving connection, and enabling the efiicient use of electric motors vfor riving the compressor which, while thoroughly efiicient at high speeds, would in starting up against heavy loads. I v

With the above objects in view, the invention will now be described in' detail in connection with the accompanying drawing and thenovel features thereof will then be specifically pointed out in the claims.

The figure of the drawing shows in vertical cross section. a compressor cylinder and its discharge or receiver connection with my proved unloading mechanism in a pre ferred form. Referring now to 'thedrawin ,iA indicates the cylinder of a horizonta compressor cylinder with suction and discharge connections B, C, respectively, a, 6 indicate the suction and 'dischar valves, respectively, located on the cylinder casting, and c'a main dischar check valve of the same character loca charge connection 0; The valves a, o, c are preferably, and as shown, of the shown and described in .United States reissued Letters Patent No. 13991, dated .Oct. '12, 1912, and United States Letters Patent No.

in the compressgr dis-' 1,341,145, dated May 25, 1920, but maybe of any other suitable type.

The means for permitting the, compressor driving motor to attain approximately full speed before compressing action be ins, comprise a by-passconnection 1O locat on the compressor discharge C at a point preferably just below the main check valve and opening to an-atmosphere connection11 through valve port 12. The port 12 is normally closed by a valve d, shown as ofthe poppet type, with its plunger 13 workingcommunicating through pipes 17, 18 with v the valve casing 14 above plunger 13 and the compressor discharge C, respectively, the latter connection being at a point in the dischargeC above the main check'valve c.- The ports 3, 4 are closed to each other by valve e when the compressor is not running. the parts being shown'in this position in the drawing. The stem of pilot valve e is connected to a speed responsive device, shownas a common centrifugal governor f, driven from the compressor motor in any suitable manner. I y

It will be obvious that,when the compressor is started and there is. no pressure in the receiver, pressure air will first flow through the main check valve c untll the receiver pressure is slightly greater than that required to open the port 12 by mov-- ing valved against the pressure of the spring 15, when valve 0 will remain closed and pressure air will be by-passed to the atmosphere through such port and pipe 1-1 until the compressor has reached the. de-' sired speed, preferably approximately full speed. When the compressor has attalned approximately full speed, the governor weights will have raised'thepilotvalve e so as to connect ports 3, 4 and permit pressure air to flow from the discharge C throu h pipe 18, ports'4, 3 and pipe 17 to the p unger casing'li, and'suchalr pressure on the larger pressure area of plunger 13 as compared wlth the area of valve 1, supplemented by'the I pressure ofthe spring fgnectionand allow air to be compressed Wthfdugh the i he k valve 0. When the 3 speed is reduced, the drooping of the governor Weights will move pilot valve (2 to close ports 3, 4 to each other and open port 3 tothe atmos here to relieve the air pressure in the va ve casing 14:, so that valve 01 is held onits seat only by the pressure of its seating spring and the "air will be bypassed to the atmosphere and the load on the motor relieved.

It will be understood that the invention is not limited to the-construction shown, but

that various changes and modifications may be made therein within the scope of the claims.

What is claimed is:

1. A speed controlled compressor unloader mechanism, consisting of a discharge connection from the cylinder, a check valve in said discharge, a low pressure by-pass connection from said discharge at a point intermediate .said discharge check valve and the cylinder, a pressure controlled valve controlling said connection, a speed responsive device, and a pilot valve controlled by said device and controlling the pressure on said pressure-controlled valve to permit it to open at low speeds and close the valve when the compressor has attained the speed desired.

2., A speed controlled compressor unloader mechanism, consisting of a discharge connection from the cylinder, a check valve in said discharge, alow pressure by-pass connection from said discharge at a point intermediate said di'sclia "ge check valve and the cylinder, a loy-pass valve controlling said connection and having difi'erential pressure areas, a connection from the compressor discharge above the main compressor check valve adapted to transmit receiver pressure air to the larger pressure area of said by-pass valve, a speed responsive device, and a pilot valve controlling said receiver connection and actuated by till) said speed responsivedevice to apply said receiver pressure, to hold the by-pass valve closed when the compressor is operating at higher speeds and-.to open the by-pass valve at low speeds for starting and stopping.

3. A speed controlled compressor unloading mechanism consisting of a discharge connection from the cylinder, a check valve/ in said discharge, a low pressure by-pass'connection from said discharge at a point" intermediate said discharge check valve and the cylinder, a valve located in said' by-pass having a large pressure area adapted to be exposed to the receiver pressure through a connection thereto and a smaller ressure area constantly ex- 0 posed-to the, cy inder pressure, and speed governor controlled pilot valve and consaid hy-pass valve casing to hold said valve closed when the compressor is operating at higher speeds and to open the by-pass valve atlower speeds. I i

4. An unloader for compressors comprising a main valve casing adapted to be connected in the discharge line of a compressor, a main discharge valve controlling the outlet from said casing to the discharge line, automatic means for producing a time element between the starting of the compressor and the opening of said main check valve, and automatic means controlled by the speed of the compressor piston for relieving the pressure remaining in the main valve casing as the compressor comes to a stop.

5. An unloader for compressors, comprising a valve casing adapted to be connected in the discharge line of a compressor, a main discharge valve controlling the outlet from said casing to the dischar e line, and operative means connected to said valve casing for automatically unloading and re-loading the compressor controlled only by the speed of the compressor piston.

6. An unloader for compressors comprising a main valve casing adapted to he connected in the discharge line of a compressor, a main discharge valve controlling the out let from said casing to the discharge line, and automatic means controlled by the speed of the compressor piston for relieving the pressure remaining in the main valve casing, as the compressor comes to a stop.

, 7. A compressor having a discharge valve, a check valve between said discharge valve and the delivery, and an unloader comprising a pressure controlled unloading valve connected with the discharge line between said compressor discharge valve and check valve, and a speed controlled valve and connections for controlling the pressure on said unloading valve, whereby the load is thrown on and 0d the compressor in accordance with its speed.

8. A. compressor having a check valve in the discharge line and an unloadercomprising a pressure controlled unloading valve connected with the discharge line on the compressor side of the check valve, and a speed controlled valve and connections for controlling the pressure on saidunloader valve to permit the opening of the valve when the compressor is stopped or running at low speed and to hold said unloader valve closed when the compressor is running at higher speeds. 1 1 1 9. An unloader forcompressors, compris ing a pressure controlled unloading valve connected with the discharge line of the compressor, a valve "for controllingthe pres sure on said unloading valvepand centrifugal means-operated hy theIcompressor-lor lie operating said last mentioned valve, whereby theload is thrown on and oil the com.- pressor under the control of said centrifugal means.

10. A compressor having a discharge valve, a check valve between said discharge valve and the delivery, and an unloader comprising a pressure controlled unloadin valve connected with the discharge line, an a speed controlled valve and connections for controlling the pressure on said unloading valve whereby the load is thrown on and off 318 compressor in accordance with its spee 11. A compressor having a check valve in the discharge line and an unloader comprising a pressure controlled unloading valve connected with the discharge line, and a speed controlled valve and connections for controlling the pressure on said unloader 12. An unloader for compressors comprise ing a pres'sure'controlled unloadln valve connected with the discharge line of t e compressor, a speed controlled governor driven by the compressor, a valve controlled by said governor-for controlh t the pressure on said unloading valve to a: u and unload the compressor, whereby the load is thrown on and oil" the compressor in accordance with its speed, and a check valve for preventing the delivery pressure irom being im upon the compressor after unloading.

In testimony whereof, I have hereunto set m hand. y MICHAEL RIESNER. 

